1. Field of Invention
This invention relates to methods and apparatus that re-calibrate scanned image data based on the marking process and materials used to form the image from which the image data was obtained.
2. Description of Related Art
In order to accurately calibrate a color scanner that scans a particular image carried on a substrate, or to re-calibrate the image data resulting from scanning an image, different calibration processes are required depending on the marking process and materials used to form the image. For example, the calibration process used to calibrate the scanner, or to re-calibrate the image data, for a photographic image is different from the calibration process that is used to calibrate the scanner, or to re-calibrate the image data, for an ink-jet-printed image, which in turn is different from the calibration process that is used to calibrate the scanner, or to re-calibrate the image data, for a xerographically-formed image.
Typically, a user wishing to scan an image must determine the marking process by which the image was marked, and then manually identify the marking process (i.e., photographic, lithographic, ink-jet, xerographic or sub-types of these large classes) to the scanner so that an appropriate calibration process can be selected.
This invention provides methods and apparatus that automatically re-calibrate image data that has been scanned, or the like, from a substrate, based on the marking process used to form the image on the substrate.
In one exemplary embodiment of the systems and methods of this invention, an initial calibration, which may be a compromise calibration between individual optimal calibrations for respective ones of a plurality of marking processes, is set before scanning the image. The marking process is then detected, and the image data is re-calibrated based on the detected marking process.
In some exemplary embodiments of the systems and methods of this invention, the marking process is detected based on spatial characteristics of the scanned image data.
In other exemplary embodiments of the systems and methods of this invention, the marking process is detected based on additional spectral information obtained from the scanned image data through additional spectral channels.
These and other features and advantages of this invention are described in or are apparent from the following detailed description of preferred embodiments.